Doug has 170 stamps in his two-book collection. his first book of stamps has 30 more stamps in it than his second book. How mwny stamps are in each book?

3 answers

x + x + 30 = 170

2x = 170 - 30

2x = 140

x = 70

He has 70 stamps in one book. How many does he have in the other book?
100
Right.